Clark County commissioners approved today the sale of 9,000 acres near Laughlin to a Chinese energy company, which plans to build a massive solar energy array and manufacturing facility on the site.

In approving the project, commissioners set benchmarks that ENN Mojave Energy must reach in the coming years or the land will return to the county.

The county’s asking price — $4.5 million — is well below two appraisals, which put the value of the acreage at between $29.6 million and $38.6 million.

But commissioners agreed that the potential economic impact of the project justifies its sale at below-market prices.

“Public bodies do this all the time in the name of jobs,” said Commissioner Steve Sisolak, whose district includes Laughlin. “Some even give away land to encourage development. We think this will be huge for Nevada.”

ENN Mojave Energy announced in June its intentions to first build a solar-panel factory, then a massive solar energy plant on land near the southern tip of the state.

The company ultimately wants to build an “eco-city”— powered by renewable energy with solar-energy manufacturing as its residents’ primary source of employment.

Armed with financing, the company seeks over the next 13 years to increase output from 280 megawatts to 840 megawatts (enough to supply about 200,000 homes) and construction from a $1 billion price tag to $6 billion.

Several benchmarks have to be met or the land reverts to the county and ENN must pay the county $4,000 per acre. The conditions are in place because the price assumes it’s being developed.

The deal requires ENN to:

• have a power-purchase agreement within 18 months

• invest at least $100 million by the end of 2014; $350 million by the end of 2016; and $1 billion by the end of 2018.

• hire 500 full-time employees at the site by the end of 2016.

• produce at its solar plant 150 megawatts by October 2016; 300 megawatts by October 2017; and 500 megawatts by 2018.

• begin construction of the second of five phases of the project by October 2016.

• complete the entire project by 2025.

The company has estimated the number of construction jobs associated with the project will grow to 2,944 by the end of 2015; permanent jobs during the first five years would number between 590 and 2,222.

Perceptions of the plant’s potential economic impact on Laughlin and Southern Nevada is highlighted by the fact that sources say U.S. Sen. Harry Reid, who visited ENN’s plant in China earlier this year, is helping work out power-purchase agreements between ENN and publicly traded or government-operated utilities.

That won’t be easy.

One example of possible pitfalls occurred in recent years in California. The state’s thirst for renewable energy may be the largest in the country, as a law was passed this year for companies to increase their renewable energy holdings to 33 percent by 2020.

But complaints about the cost of renewable energy have grown. In May, the PUC issued a draft resolution rejecting an agreement that would have allowed North Star Solar LLC to build a photovoltaic plant because of the cost. After the company cut expenses by some 20 percent, the plans were approved in October.